In order to implement production planning and manufacturing cost management with precision, it is necessary to accurately estimate input data composed of the operation time information about each manufacturing process of each product. The methods for estimating operation time include: (1) a method of dividing the operation into elementary operations (to move, to turn a screw, etc.), before aggregating predefined elementary operation times based on product specifications to calculate the operation time; and (2) a method of calculating the time actually required to perform the operation (actual operation time) from operation result information, and categorizing the results of the calculation by product specification and by manufacturing condition. The method (1) above has the problem of requiring a large amount of man-hours in measuring the elementary operation times and dividing the operation into the elementary operations, as well as the problem of the aggregated elementary operation times resulting in a divergence from the actual operation time. Thus the method (2) above is generally employed.
In the past, an example of calculating operation time using operation result information such as the method (2) above has been disclosed by PTL 1, the disclosure being the method of calculating individual operation times based on the operation start date and time and on the operation end date and time from operation result information, the results of the calculation being categorized by product specification and subjected to statistical processing, thereby calculating the operation time per product specification. PTL 2 discloses a method of calculating individual operation times in a manner similar to that of PTL 1, the disclosed method categorizing the calculated individual operation times by event (equipment failure, change of job count within a lot, etc.) that occurred on the manufacturing floor while the operation was being implemented, whereby the operation time is calculated from the currently occurring event.